1. Field of the Invention
This invention relates to a primer composition, and more particularly to a primer composition suited for bonding curable liquid fluorine rubber to silicone rubber.
2. Description of the Prior Art
Silicone rubbers are used in many fields because of their good weatherability, heat resistance and electrical properties. Silicone rubbers, however, have a limit in their use because of their poor solvent resistance and chemical resistance. Accordingly, curable liquid fluorine rubber is now available as a promising material for modifying the surface of silicone rubber. This curable liquid fluorine rubber has a low viscosity before it cures, and is suited for coating. It cures upon heating at a temperature of about 150.degree. C. after coating, to form a cured coat having a rubberlike elasticity. The cured coat thus obtained has good solvent resistance and chemical resistance.
However, the cured coat of the curable liquid fluorine rubber has a low adhesion to silicone rubber, and hence it has the disadvantage that only a low durability can be obtained in respect of solvent resistance and chemical resistance. Nevertheless, no primers useful for improving the adhesion between the liquid fluorine rubber and the silicone rubber are known in the art.